Effects of the Lapidus Arthrodesis and Chevron Bunionectomy on Plantar Forefoot Pressures

Hallux valgus with or without first ray insufficiency has been strongly implicated as a contributing factor in lesser metatarsal overload. The principle goals of a bunionectomy are to relieve the pain, correct the deformity, and restore first metatarsophalangeal joint congruity. Until now, little evidence has been available to assess the effects of bunionectomy procedures on forefoot pressure. The primary aim of the present prospective study was to evaluate the preoperative and postoperative plantar pressures after 2 specific bunionectomies: the chevron bunionectomy and Lapidus arthrodesis. A total of 68 subjects, 34 in each group, were included for radiographic and pedographic evaluation. Both procedures demonstrated radiographic improvements in the mean intermetatarsal and hallux abductus angles. The mean hallux plantar pressure decreased significantly in both procedure groups (p<.001). However, Lapidus group exhibited an increase in the mean fifth metatarsal head plantar pressure (p=008) and pressure under the fifth metatarsal as a percentage of the total forefoot pressure (p=01). Furthermore, the pressure under the second metatarsal as a percentage of the total forefoot pressure decreased significantly (p=01). This study suggests that the Lapidus arthrodesis and chevron bunionectomy both provide correction for hallux valgus deformity, but when comparing forefoot load sharing pressures, the Lapidus arthrodesis appeared to have greater influence on the load sharing distribution of forefoot pressure than did the bunionectomy employing the chevron osteotomy.